Notifications should be customized by study

• types of notifications should be enabled/disabled per study
• period times should be configurable per study

assigned to @piotr.gawron

created branch 191-notifications-should-be-customized-by-study

mentioned in merge request !104 (merged)

closed via merge request !104 (merged)

closed via commit 695d7c5f

changed milestone to %0.11.0